The present invention relates to the art of equipment safety and protection monitoring. The invention finds particular application in conjunction with CT scanners and will be described with particular reference thereto. However, it is to be appreciated that the invention is also applicable to other medical diagnostic scanners, such as magnetic resonance scanners, digital x-ray scanners, and the like. Further, the present invention may also find utility in conjunction with other computer based or controlled equipment.
Heretofore, CT scanners have commonly included a gantry system in which the x-ray tube, radiation detectors, x-ray tube assembly rotation motors, cooling equipment, and other associated hardware and controls were mounted. A central processing unit was commonly mounted in another cabinet but interconnected electronically with the gantry. The central processing unit included the computer software and memory for processing radiation intensity data from the gantry to generate image representations and other diagnostic information. The central processing unit could also contain service and set-up software or memory capacity for loading such service software. An operator control panel included the appropriate control buttons, switches, disk drives, display monitors, and the like such that the operator could cause the gantry to take one or more CT scans. The operator control panel also accessed the appropriate software in the central processing unit to process the CT data and generate selected images or other diagnostic displays. For system tune-up and repair, service software could be entered through the disk drives on the console. Appropriate commands from the keyboard controlled the service software and entered software based corrections. System malfunctions or failures could be indicated on the console display or by LED lights located in the console and the central processing unit.
Although the prior art CT scanners indicated abnormal and potentially injurious operating conditions, the operator was under no compulsion to heed the warnings. Rather, the operator could continue to operate the system even under such abnormal operating conditions as overheating of the x-ray tube, overheating of the radiation detectors, and other conditions that could damage or destroy expensive hardware components. For patient safety, it was generally considered inappropriate to overrule the operation and shut-down the CT scanner system when components were operating a temperature or other range that would cause premature but not imminent failure. The patient in the scanner, in some instances, was in a life threatening situation in which the CT scans were a necessary diagnostic tool. This concern for patient safety which allowed operations of the scanners outside of normal operating parameters tended to increase requests for warranty repairs.
Another problem with the prior art CT scanners resided in the use of unauthorized software. For example, third party service technicians could enter and use their own software which improperly or inadequately diagnosed system errors. Even if the manufacturer's software was permanently stored in the CPU and could be accessed, third party technicians often misused the software, improperly diagnosed system failures or miscalibrated the system. As another example, third party image data processing software not designed for this hardware and pirate copies of software designed for this hardware could be entered into the CPU. The use of third party image or patient data software designed for other hardware could cause inaccurate and even incorrect diagnostic readings. Moreover, use of third party and pirate software caused a major financial loss to the manufacturers. The very high number of man hours that go into software development and improvement represent a high cost to the manufacturers which is amortized over copies of the software as it is sold. Pirate software not only cost sales to the manufacturers, but also reduces the number of software copies over which the development costs are amortized--hence, raises costs to honest purchasers.
Commonly, CT scanners have a single push-button for starting a scan. Once the button is pushed, the scan routine is automatically started and completed irradiating the scan circle with radiation. If the scan is inadvertently started, any portion of a patient or technician in the scan circle is needlessly irradiated.
The present invention contemplates a new and improved safety monitor system for CT scanners which overcomes the above referenced problems and others.